We are taking an NFL Nation look at a team's four-man Mount Rushmore.Choosing the four-man shrine for the San Francisco 49ers is a difficult tast. This is a team rich in history, dating well before the AFL-NFL merger. Anyone can pick a combination that would work. However, I'm keeping it simple. I am taking four men who were instrumental to the team's dynasty in the 1980s.Bill Walsh: The architect of the 1980s 49ers was an offensive innovator and the leader of this franchise There would be no dynasty if it weren't for Walsh.